In order to let you know more about the 100G QSFP28 optical transceivers, this article ETU-LINK will share the relevant knowledge of the 100G QSFP28 optical module with you in a question-and-answer format.

Q1: How many types of 100G QSFP28 optical transceivers?

A1: At present, the 100G optical transceiver on the market include SR4, eSR4, PSM4, CWDM4, CLR4, LR4, ER4, ZR4, and the relevant parameters can be found in the table below.

Q2: What is the difference between 100G CWDM4/CLR4 and LR4 optical Transceivers?

A2: The wavelengths of the two are different, and the transmission distance is also different. The 100G CWDM4/CLR4 optical module adopts CWDM coarse wavelength division technology, and the working wavelengths are 1270, 1290, 1310, and 1330 nm, while the 100G LR4 optical module adopts LAN WDM technology, and the working wavelength is 1295, 1330 nm. 1300, 1304, 1309nm.

Q3: Where are the main applications of 100G QSFP28 optical transceivers?

A3: 100G QSFP28 optical transceivers are mainly used in the interconnection of 100G QSFP28 ports of data center core switches and core routers.

Q4: Can 100G optical module be connected to 25G optical transceivers?

A4: Yes, but only 100G optical transceivers with MPO interface (SR4, eSR4, PSM4) can be connected to 25G optical modules, but we need to use MPO-LC branch jumpers to connect 100G optical modules and 25G optical modules. Multi-mode 100G SR4/eSR4 optical modules can be connected to multi-mode 25G SR optical modules, and single-mode 100G PSM4 can be connected to 25G LR.

Q5: What is the effect of enabling and disabling the FEC function on the 100G optical transceivers?

A5: The FEC function is used in high-speed optical  transceivers such as 100G. Usually, when this function is turned on, the receiving sensitivity of the optical module will be enhanced, and the transmission distance of the high-speed optical module will be longer than when the FEC function is not turned on. Although the FEC function has two advantages of forward error correction and increased transmission distance, it will inevitably cause some packet delays in the process of correcting bit errors. Therefore, not all high-speed optical modules are recommended to enable this function. For example, when using a 100G QSFP28 LR4 optical module, it is not recommended to enable the FEC function. 100G optical modules mainly rely on configuring the FEC function on the device side to implement error correction, so the switch needs to support the FEC function. Usually, the switches that support the FEC function have the FEC function enabled by default. In addition, it should be noted that if the FEC function is enabled on the A-end optical module, the B-end optical module must also enable this function, otherwise the interface will not go Up.

Under the influence of the epidemic, the global dataization process has accelerated significantly. ETU-LINK 100G QSFP28 optical transceivers have been used by most data centers, and will have broad application prospects in medium and large data centers in the future.